68
10.2  MTL5018AC single-pole, changeover relay,  
two-channel, switch/proximity detector with line fault detection 
and phase reversal
 
The MTL5018AC modules enable each of two safe-area loads to be relay-controlled by switches 
or proximity detectors in a hazardous area. 
Line fault detection (LFD) and output phase reversal facilities are included (see section 6.1).
10.2.1  Wiring connections
See figure 10.1 for wiring connections. 
Note: Reactive loads must be adequately suppressed.
10.2.2  Line fault detection
(See section 6.1 for definition of a line fault)
On each channel, input line faults (open- or short-circuit) are indicated by an LED and the  
de-energising of the output. LFD is enabled/disabled by switches located on the top of 
the module.
Note: that if the LFD facility is enabled for switch inputs, the resistors shown in 10.1 and 10.2 
MUST be fitted.
Terminal Function
1 Input –ve (Ch 1)
2 Input +ve (Ch 1)
3
4 Input –ve (Ch 2)
5 Input +ve (Ch 2)
6
7 Normally-closed contact (Ch 2)
8 Common (Ch 2)
9 Normally-open contact (Ch 2)
10 Normally-closed contact (Ch 1)
11 Common (Ch 1)
12 Normally-open contact (Ch 1)
13 Supply N
14 Supply L
Hazardous area Safe area
Figure 10.1: MTL5018AC wiring diagram and connections